Rotating stall can arise in a gas turbine engine when operating conditions conspire to reduce the flow rate through the engine, until flow through the engine ceases to be even and symmetrical and breaks down in some regions in which flow over the compressor of the gas turbine has become unstable. The unstable regions will typically rotate within the gas turbine. The overall flow rate through the engine reduces, with other significant consequences, such as excessive temperature and vibration and a loss in thrust. Recovery from rotating stall can be difficult to achieve and thus, the recurrence of rotating stall represents a significant operational risk to an engine.
Accordingly, it is desirable to be able to model the onset of rotating stall within a gas turbine engine, but the computational power required to do so can be excessive.